With conventional tape copying methods, the information contained on a prerecorded tape is reproduced by a tape-playing device and transmitted via a transmission path to a recording device and recorded on another tape. Ideally, at the end of the tape copying process the same information is contained on both the newly recorded tape and the original tape. Supplementary information which, with certain recording standards--for example, the VHS standard--is used for the internal control of the playback operation and which is recorded in addition to the actual information on the original tape is not copied. The control information is generated during the initial recording for use during replay to synchronize the switch over between several scanning heads. The control, or synchronization, pulses are recorded on a longitudinal track, called a control track (CTL), which is parallel to the tape edge. The control pulses consist of sharp magnetic transitions from north to south or from south to north. Accordingly, two successive transitions in the same direction establish a definite time span of, for example, 40 msec, during the recording. The transitions in the other direction are not required for synchronization and can therefore, within certain limits, be varied in their relative positions within the 40 msec time span, without impairing the original synchronization function of the control track.
The ability to vary the relative positions of the south to north transitions can be used for digital coding. Such a use is made in the VHS standard in order to enable magnetic marks to be positioned on the magnetic tape--for instance, for the precise image location of particular points in a recording. For that reason, there are two types of marks, the so-called VISS (VHS index search system) mark which represents unchangeable digital information, and the so-called VASS (VHS address search system) mark which contains an individual address in digitally coded form.
When a relatively short program message is recorded on a long tape it is advantageous to simultaneous mark the start of a recorded material, for the purpose of exactly locating the beginning of the material in the playback mode. If a prerecorded tape containg such marks is copied, using prior art copying methods, only the message information is recorded. The location marks are not transfered and recorded since they are located in a region of the replay tape which is provided for internal device playback mode control purposes and cannot be accessed or utlized by the user.